This invention relates in general to vehicle engines and in particular to an improved composite intake manifold assembly for use in such a vehicle engine and method for producing the same.
An intake manifold assembly of a multi-cylinder engine includes a plurality of branched air passageways or ducts. Each of the air passageways defines a generally tubular runner having an air intake port and an opposite air inlet port. The air intake port of the runner is connected to an associated plenum which supplies atmospheric, turbo, or supercharged air to the runner intake port, and the air inlet port is connected to a flange which is connected to an associated inlet port of each cylinder head of the engine to supply the air from the runner to each cylinder head. Conventional intake manifold assemblies arc constructed of cast iron, magnesium, aluminum, and plastic.
A typical aluminum intake manifold assembly is produced entirely by conventional casting process. These manifolds typically include a plurality of tubes disposed having first ends connected with the outlet holes of an air intake plenum, and second opposite ends connected with the associated holes of a flange member which is adapted for mounting to a cylinder head of the engine. Since the tubes are usually U-shaped, the manifold cannot be cast in one piece but rather must be cast in two sections, with one section comprising a length of the tubing cast integrally with the plenum and the other section comprising the remaining length of the tubing cast integrally with the flange member. The halves must then be joined together with bolts and a gasket or other suitable hardware to complete the manifold, further adding to the cost and complexity of the manifold.
A typical plastic multi-piece manifold assembly includes an upper half shell and a lower half shell which are joined together by a welding process. In some instances the plastic multi-piece manifold assembly includes one or more inner shell pieces which are disposed within the upper and/or lower half shells. The inner shell can be lower partial inserts which are secured to lower half shell; upper partial inserts which are secured to the upper half shell, or both lower and upper partial inserts which are secured to the respective lower and upper half shells. The inserts are typically joined to the associated half shell by a conventional heat staking process or welding process. In some instances, a plurality of individual blow molded tubes are disposed within the upper and lower half shells and joined thereto by a conventional heat staking process. In both types of constructions, the inserts or the inserts in cooperation with upper or lower half shells define a corresponding number of runner paths through which air is supplied to the associated cylinder head of the engine.